thirtieth day of the month; thirty days
thirty-first day of the month; thirty-one days
Thirty Years' War (1618-1648)
turning thirty and therefore becoming independent; at thirty, one stands on one's own
32nd anniversary of death
thirty-three temples sacred to Kannon (Avalokitesvara)
32nd note; demisemiquaver
the thirty guardian deities (a different one for each day)
36 Initials (system for transcribing initial consonants of Middle Chinese)
cesium 137 (Cs-137); caesium 137